Common issues we see
- Architectural and engineering calculation errors, specification gaps and coordination failures between disciplines
- Defective or unsuitable materials specified, including non-compliance with British Standards or Building Regulations
- Design and build employer’s requirements versus contractor’s proposals disputes, including responsibility for fitness for purpose language
- Water ingress, fire safety non-compliance, cladding and facade defects, structural movement and stability concerns
- M&E design deficiencies leading to overheating, inadequate ventilation, acoustic failures or excessive energy use
- Inaccurate surveys or reports by consultants and resulting scope or cost overruns
- Collateral warranty and third-party rights claims against designers and design and build contractors
- Professional indemnity insurance coverage issues, notifications and exclusions
Legal framework and your rights
Design liability may arise in contract and in tort. Professionals usually owe a duty to exercise reasonable skill and care; some contracts impose a higher fitness for purpose obligation, particularly on design and build contractors. Allocation of risk under forms such as JCT and NEC, collateral warranties or third-party rights, and any limitation or exclusion clauses must be analysed carefully.
- Duties and standards: contractual duties, implied terms, professional standards and the Bolam/Bolitho approach to professional negligence
- Compliance: Building Regulations, British Standards, technical approvals and statutory duties, including the Building Safety Act 2022 regime
- Limitation: typical periods are six years for simple contracts and 12 years for deeds; negligence claims may benefit from the latent damage provisions, and certain Defective Premises Act 1972 claims now have extended periods under recent legislation
- Quantum: reasonable cost of rectification, diminution in value, delay and prolongation costs, loss of profit, additional preliminaries and professional fees
- Causation and contribution: apportionment between parties, contributory negligence and contribution claims under the Civil Liability (Contribution) Act 1978
- Pre-action protocol: the construction and engineering disputes protocol encourages early exchange of information and expert input before proceedings
Routes to resolution
We deploy the right forum for your case and timetable. Many design disputes are resolved swiftly through adjudication to maintain cashflow. Others require mediation, expert determination, arbitration or litigation in the Technology and Construction Court. We plan the technical strategy with your experts from the outset so that your evidence is admissible and persuasive in any forum.
- Urgent adjudications under the Housing Grants, Construction and Regeneration Act
- Without prejudice negotiations and structured mediations
- Expert determination for discrete technical issues
- Arbitration under contract terms or by agreement
- Technology and Construction Court proceedings for high-value or complex claims
Why choose us
Stephensons is a nationally respected, SRA-regulated law firm with decades of experience resolving construction quality and defects disputes. Our teams act across England and Wales for clients ranging from public bodies and developers to specialist subcontractors and insured professionals, bringing sector know-how and commercial pragmatism to every case.
- Quality assured: we operate robust quality and risk management systems and are committed to clear advice and proactive case management
- Recognised capability: our lawyers are experienced in high-stakes adjudications and TCC litigation involving complex design and engineering issues
- Technical fluency: we work seamlessly with leading independent experts in architecture, structural engineering, M&E and fire safety
- Integrated support: our regulatory and criminal law teams can advise alongside us where there are HSE, building safety or enforcement investigations
- Transparent costs: clear scoping, budgets and regular updates, with stage-based and fixed-fee options where appropriate
- Client service: responsive, practical and focused on outcomes that protect your programme, budget and reputation
How we can help
We provide end-to-end support on design faults and professional negligence disputes, from immediate triage to recovery of losses and enforcement. Our approach is to stabilise the project, preserve evidence and deliver a strategic plan tailored to your goals.
- Early case assessment, document review and risk mapping
- Appointment and management of independent experts and forensic investigation of defects
- Contractual analysis of design obligations, exclusions and notification requirements
- Pre-action correspondence, letters of claim and protocol-compliant steps
- Rapid adjudications to address liability, valuation and interim recovery
- TCC proceedings, arbitration and mediation representation
- Insurance notifications, coverage advice and coordination with insurers
- Drafting and pursuing claims under collateral warranties and third-party rights
- Project rescue strategies, variation and settlement agreements
Who we act for
We act for a wide range of participants in the construction and engineering sector, bringing balanced insight to each dispute.
- Employers, housing providers, developers and asset owners
- Main contractors, design and build contractors and specialist subcontractors
- Architects, structural engineers, M&E designers and other consultants
- Project managers, contract administrators and employer’s agents
- Insurers and insured professionals
Funding and costs
We will discuss the most suitable funding options for your circumstances. Depending on the case, we can offer phased or fixed fees for defined stages, competitive hourly rates, and explore alternative funding and insurance solutions where appropriate. We will always provide clear estimates and keep you updated on costs as the matter progresses.
Frequently asked questions
Below are answers to common questions about design liability, negligence and defective design claims in construction.
What counts as a design fault versus a workmanship defect
A design fault arises where the design itself is deficient, unsafe, non-compliant or unfit for its intended purpose, even if constructed perfectly. Workmanship defects arise from poor execution of a sound design. Many disputes involve both: for example, an inadequate waterproofing design compounded by poor installation. A careful technical investigation is required to allocate responsibility correctly.
Who can I claim against
Potential defendants include architects, engineers, design and build contractors, specialist designers, and sometimes product specifiers. Claims may be brought under your building contract, a consultant’s appointment, a collateral warranty or third-party rights, and in negligence where a duty of care is owed. We will identify all viable routes and parties, including insurers.
What are the time limits for bringing a claim
Time limits vary. As a broad guide, claims under simple contracts are generally six years from breach and under deeds 12 years. Negligence claims may benefit from the latent damage provisions, which run from the date of knowledge, subject to a longstop. Some building safety and defective premises claims have extended limitation periods following recent legislative changes. Early advice is vital to avoid missing a deadline.
Do I need an expert
Yes, expert evidence is pivotal in design fault and professional negligence disputes. An independent architect, engineer or relevant specialist will help establish the standard of care, breach, causation and the scope and cost of remedial works. We will help source and instruct the right expert and ensure their input is effective across adjudication, mediation and litigation.
How do design obligations differ under jct and nec forms
Under JCT, contractors typically owe reasonable skill and care unless the contract expressly imposes fitness for purpose. Under NEC, obligations are driven by the Scope and can be amended to allocate design risk differently. Each contract must be read closely, including any employer’s requirements, contractor’s proposals, technical schedules and amendments that shift or heighten design responsibility.
Can I recover my legal costs in adjudication
As a starting point, each party generally bears its own legal costs in adjudication unless the contract provides otherwise or the parties agree a costs regime. The adjudicator’s fees are usually allocated between the parties, often following the event. In court or arbitration, the usual rule is that the losing party pays a proportion of the winner’s reasonable costs, subject to the court’s discretion.
What if the designer’s professional indemnity insurer declines cover
Coverage may be disputed due to notification issues, exclusions or alleged dishonesty. We can advise on policy response, assist with notifications and challenge declinatures where appropriate. Claims can proceed against the professional regardless; enforcement routes against insurers may also be available depending on the circumstances.
Do collateral warranties and third-party rights help
Yes, if you are not a party to the designer’s appointment, collateral warranties or contractual third-party rights can give you a direct claim. We will review your documents to confirm rights, assignment provisions and any limitations or caps that may affect recovery.
Will pursuing a claim delay my project
Not necessarily. We frequently use adjudication to secure swift decisions on liability and interim payments while projects continue, and we work with your team to implement remedial solutions in parallel. Our focus is to minimise disruption and protect your critical path.
Contact us
For specialist advice on design faults and professional negligence disputes, call Stephensons on 0161 696 6170. Alternatively, fill in our enquiry form for a callback and one of our construction disputes solicitors will get in touch promptly.
Early engagement is key. If your matter is urgent, tell us about any looming deadlines, adjudication timetables or safety concerns so we can prioritise immediate protective steps.
